Cigarette filter

ABSTRACT

A cigarette filter is provided which comprises a pair of complemental sections formed of smoke-impervious material and arranged in registered relation and affixed to one end of a tobacco rod. Each complemental section is provided with an elongated indentation closed at one end. Sandwiched between the indentations of the complemental sections and cooperating therewith to form a pair of elongated smoke passageways is a thin perforated membrane. A predetermined number of the membrane perforations effect communication between the passageways whereby smoke flowing from one passageway to the other attains a high velocity while passing through a membrane perforation and the high-velocity smoke impinges against a surface of the passageway and causes solid and liquid particles entrained in the emitted smoke to be deposited on said surface.

United States Patent [72] Inventor Hoyt S. Beard Winston-Salem, N.C.

[21 App]. No. 865,344

[22] Filed Oct. 10, 1969 [45] Patented Jan. 4, 1972 [73] Assignee R. J. Reynolds Tobacco Company Winston-Salem, N.C.

[54] CIGARETTE FILTER 3,367,343 2/1968 White et a1. 131/201 X 3,472,238 10/1969 Blount et a1. 131/201 X FOREIGN PATENTS 1,094,642 12/1967 Great Britain 131/261 B Primary ExaminerAldrich F. Medbery Assistant Examiner.l. F. Pitrelli Att0rneyPendleton, Neuman, Williams & Anderson ABSTRACT: A cigarette filter is provided which comprises a pair of complemental sections formed of smoke-impervious material and arranged in registered relation and afiixed to one end of a tobacco rod. Each complemental section is provided with an elongated indentation closed at one end. Sandwiched between the indentations of the complemental sections and cooperating therewith to form a pair of elongated smoke passageways is a thin perforated membrane. A predetermined number of the membrane perforations effect communication between the passageways whereby smoke flowing from one passageway to the other attains a high velocity while passing through a membrane perforation and the high-velocity smoke impinges against a surface of the passageway and causes solid and liquid particles entrained in the emitted smoke to be deposited on said surface.

PATENTEB JAN 4872 SHEET 2 BF 2 CIGARETTE FILTER BACKGROUND OF THE INVENTION I-Ieretofore various cigarette filters have been provided which because of certain design characteristics are beset with one or more of the following shortcomings: (a) the filter is formed of a plurality of component parts; (b) the assembly of the various component parts is difficult, awkward, and timeconsuming; (c) the filter is ineffective in removing solid and/or liquid particles from the smoke; (d) the filter has a deleterious effect on the taste and aroma of the smoke; and e) the cost of the filter is inordinately high.

SUMMARY OF THE INVENTION Thus, it is an object of this invention to provide a cigarette filter which avoids the aforenoted shortcomings.

It is a further object of this invention to provide a cigarette filter which may be assembled by utilizing techniques and methods well known and understood in the cigarette-making art.

It is a still further object of this invention to provide a cigarette filter wherein a minimum number of component parts are required and said parts may be formed at the time said filter is to be assembled thereby eliminating or minimizing the need for maintaining large inventories of said parts.

Further and additional objects will appear from the description, accompanying drawings, and appended claims.

In accordance with one embodiment of the invention a filter is provided which is affixed to one end of a tobacco rod. The filter includes a pair of complemental sections each fonned of smoke-impervious material and having a substantially semicylindrical configuration. An elongated, longitudinally extending indentation is provided in a planar surface formed in each complemental section. Each indentation has a closed end. The complemental sections are disposed in registered relation so that the planar surfaces thereof are in close proximity but separated from one another by a thin perforated membrane. The membrane cooperates with the section indentations so as to form elongated passageways through which the smoke is caused to flow successively. The indentation of one section is inverted with respect to the other section indentation; however, the closed ends of the indentations are in registration and one passageway is in communication with the other passageway only through a predetermined number of the membrane perforations. The perforations are of such size that the smoke upon passing therethrough attains a very high velocity. The high velocity smoke upon being emitted from the membrane perforation impinges against an adjacent surface forming a part of the passageway and causes the solid and/or liquid particles entrained in the smoke to be deposited upon said surface.

DESCRIPTION For a more complete understanding of the invention reference should be made to the drawings, wherein:

FIG. I is an enlarged fragmentary side elevational view of one form of the improved cigarette filter and having portions thereof shown in longitudinal section.

FIG. 2 is an enlarged top perspective view of the complemental sections comprising parts of the filter shown in FIG. 1.

FIG. 3 is an enlarged top perspective view of the perforated membrane shown in FIG. 1.

FIG. 4 is a fragmentary side elevation view of one form of the apparatus utilized to form in the complemental sections of FIG. 2.

FIG. 5 is an enlarged fragmentary perspective view of the infeed end of the apparatus shown in FIG. 4.

FIG. 6 is an enlarged fragmentary perspective view of the formed member discharged from the apparatus of FIG. 4 and prior to the complemental sections being cut therefrom.

FIG. 7 is a fragmentary perspective view of a modified form of apparatus utilized in simultaneously forming two members of the type similar to that shown in FIG. 6 but with said members disposed in inverted relation.

FIG. 8 is a sectional view taken along line 88 of FIG. 7.

Referring now to the drawings, and more particularly to FIG. 1, a preferred form of the improved filter I0 is shown affixed to one end of a tobacco rod 11'. The filter includes a pair of complemental sections 12 and 13 both of which are formed of a smoke-impervious material such as a foam plastic (e.g. expanded polystyrene). Each section 12 or 13 is of like semicylindrical configuration, so hat, when the sections are assembled, they will have a cross-sectional configuration which closely resembles that of the tobacco rod end Ila.

An elongated indentation 14 is formed in the planar surface 12a or 13a of each section 12 or I 3. Each indentation is closed at one end [4a. A portion 14b of the indentation 14 formed in surface 13a and disposed adjacent to the closed end 14a is raised; that is to say, the depth of the indentation at portion 14b is less than the depth of the remainder of the indentation.

The planar surfaces 12a and 13a of the sections when assembled, are disposed in registered close proximity but separated from one another by a thin perforated membrane 15, see FIGS. 1 and 3. The membrane may be formed from a strip of thin paper, foil, or plastic film and have a thickness of from about 0.0003 inch to about 0.010 inch. In the membrane 15 shown in FIG. 3, there is provided a centrally disposed longitudinally extending row of perforations 16. Each perforation is round and has a diameter of from approximately 0.008 inch to approximately 0.012 inch. The diameter size will depend upon the number of perforations used so that the initial pressure drop in the filter will be approximately 2 inches H,O. If desired, more than one row of perforations may be formed in the membrane.

It will be noted in FIG. I, that, when the sections are assembled, the open end Me of one indentation 14 faces upstream and communicates with the rod end I la, and the open end 14c of the other indentation 14 faces downstream. The indentation 14 of section 12 cooperates with membrane 15 to form a shallow elongated passageway 17 through which the smoke initially flows upon leaving the end 11a of the tobacco rod 1 l.

The indentation 14 in section 13 in a like manner cooperates with membrane 15 to form a shallow elongated passageway 18 through which the smoke subsequently passes after having passed through a predetermined number of membrane perforations 16. The number of perforations through which the smoke passes, upon flowing from pasageway 17 to passageway 18, will be determined by the extent of overlap of the indentation closed end portions, and the size of the membrane perforations.

Dueto the small size (e.g. 0.010 inch) of the perforations l6 and the limited number thereof in communication with passageways l7 and 18, the smoke is emitted from the communicating perforations 16 at a very high velocity (e.g. 40-200 fps.). The emitted smoke impinges against the adjacent end portion 14b of the indentation 14 formed in complemental section 13 and thus, the solid and/or liquid particles entrained in the smoke are deposited upon the end portion 14b, before the smoke continues to flow out through the remainder of the passageway 18. The distance the impingement wall 14b is disposed from the membrane perforations 16 is from about 0.008 to about 0.100 inch.

The membrane 15 is normally adhesively secured to both planar surfaces 12a and 13a. The assembled sections 12 and 13 and membrane 15 are afi'ixed to the rod end 11a by a sleeve 20 of suitable tipping paper.

The assembly of the sections 12 and 13 with membrane 15 as well as affixing the filter to the rod end may be readily accomplished by apparatus and techniques well known in the cigarette-making art.

The formation of the complemental sections 12 and 13 may be accomplished by various apparatus; two forms 21 and 22 of said apparatus are shown in FIGS. 4 and 7, respectively. In both instances the complemental sections are formed in a continuous manner.

Apparatus 21, as shown in FIGS. 4 and 5, includes a feed nozzle 23 from which a continuous stream 24 of molten plastic is discharged and directed towards the point of the initial contact between a pair of die belts 25 and 26. Belt 25 is supported and driven by a pair of horizontally spaced pulleys or sprockets 27a and b. Belt 26 in a like manner is supported and driven by a second pair of horizontally spaced pulleys or sprockets 28a and b. Both sets of pulleys may be driven by a common source, not shown.

Corresponding pulleys 27a28a and 27b-28b are disposed in vertical alignment. Belt 25 includes a plurality of male mold pieces or dies 30 which are arranged in end to end relation and are pivotally interconnected so as to permit the belt to pass about the peripheries of the pulleys 27a and b. Each piece 30 has an outwardly facing planar surface 30a on which is disposed an elongated embossment 31. The embossment 31 is shaped so as to impart the desired configuration to the indentation 14.

Belt 26 in a similar manner comprises a plurality of pivotally interconnected female mold pieces or dies 32. Each piece 32 has the outer surface 320 thereof provided with an elongated semicylindrically shaped recess 32b. The shape of recess 32b conforms to the rounded exterior of the section 12 or 13.

It will be observed in FIGS. 4 and 5 that the belts 25 and 26 during a certain segment A of travel move together in a linear horizontal direction during which time corresponding mold pieces on the respective belts are in contact with one another so as to form the desired mold to receive the plastic stream. When corresponding pieces are moving through travel segment A, portions of the planar surface 30a of the male piece 30 are in abutting sealing engagement with corresponding portions of planar surface 320 of the female piece 32. In addition to portions of the planar surfaces being in engagement with one another, the successive mold pieces forming each belt are adapted to be disposed in end to end abutting sealing relation so as to prevent leakage of the injected plastic during expansion thereof and while the mold pieces are moving as a unit through segment A of travel.

As noted in FIG. 5, the molten plastic stream 24 is discharged from nozzle 23 onto the recess 32b of female mold piece 32 just prior to the latter coming into abutting contact with the corresponding male mold piece 30. Once the female mold piece has been charged with the molten plastic, it moves into registered abutting engagement with the corresponding male mold piece 30 and then the two mold pieces move horizontally as a unit between a pair of vertically disposed elongated pressure plates 33 and 34. The plates retain the corresponding or complemental mold pieces in proper registered sealed relation as they move through travel segment A and prevent separation of the mold pieces during expansion of the plastic charge. It is desirable that an excess charge of molten plastic be disposed within the mold cavity formed by the corresponding mold pieces so that all of the details embodied in the surface configuration of the cavity will be accurately imparted to the molded product 35, see FIG. 6. As the closed mold pieces move along the travel segment A curing (full expansion) and cooling of the injected plastic occur prior to the elongated product 35 being discharged at the downstream end D of travel segment A. At downstream end D the belts separate from one another and move about their respective pulley 27b or 28b.

The discharged product 35, as noted in FIG. 6, is one continuous semicylindrically shaped rod having a flat planar surface in which is formed a plurality of like indentations l4 arranged in uniform longitudinally spaced relation. The rodlike product 35 is then directed past a suitable cutter; (only the cutting plane CC thereof being shown in FIG. 6) where individual or multiple complemental sections 12 or 13 of proper dimension are severed therefrom.

The speed of travel of the mold pieces through segment A will be determined by the amount of the injected plastic and the curing and cooling characteristics of the plastic. Cooling apparatus may be added which is located in the vicinity of segment A thereby increasing the speed of travel of the belts therethrough.

While apparatus 21 is shown comprising only one pair of die belts 25 and 26, it is to be understood of course that additional pairs of die belts may be utilized so that both complemental sections 12 and 13 can be formed simultaneously. With such an arrangement, the additional belts can be disposed in sideby-side relation with belts 25 and 26 and the sprockets utilized to drive the additional belts could be keyed to the respective axles for sprockets 27a-b and 28a-b.

In the modified apparatus 22, shown in FIGS. 7 and 8, two complemental elongated rodlike members 35 and 35' are simultaneously formed from which the complemental sections 12 and 13 of the filter are eventually produced in a manner to be described more fully hereinafter. Apparatus 22 includes a pair of longitudinally spaced nozzles 36 and 37 which are adapted to feed streams of molten plastic to form respectively rodlike members 35 and 35 Cooperating with nozzles 36 and 37 are a pair of endless belts 38 and 40. Belt 38 is formed of wide tapelike material which is capable of being successively shaped into an elongated channel-shaped member and then a tubular member during certain consecutive segments of travel E and F of the belt, see FIG. 7. Belt 38 is supported and driven by a pair of longitudinally (horizontally) spaced pulleys 41a and b. Belt 40 in a similar manner is supported and driven by a second pair of longitudinally spaced pulleys 42a and b. Pulleys 41a and 42a are disposed in substantial vertical alignment, whereas pulley 42b is elevated relative to but downstream of pulley 41b, see FIG. 7.

Just prior to belt 38 passing between pulleys 41a and 4241, the elongated edges thereof are plowed upwardly by any suitable means so as to form a substantially U-shaped channel. Onto the belt channel is deposited a stream of molten plastic from nozzle 36. The lower portion of the channel-shaped belt 38 at this point confonns substantially to the exterior configuration of complemental section 13.

Belt 40, on the other hand, is formed of a thin tapelike material having on one surface thereof a plurality of axially aligned longitudinally spaced protuberances or die pieces 43 which are shaped so as to form a plurality of indentations 14 in the rodlike member 35 produced at the downstream end of the apparatus. On the opposite surface of belt 40 there is provided a plurality of axially aligned longitudinally spaced protuberances or die pieces 44, see FIG. 8, which are shaped to form the desired indentations in rodlike member 35 The disposition of die pieces 43 may be slightly ofi'set longitudinally with respect to die pieces 44. The amount of ofiset will correspond substantially to the amount of offset which occurs between passageways l7 and 18 in the assembled filter as seen in FIG. 1.

Once the stream of plastic has been deposited onto the belt channel formed just ahead of pulley 42a, a portion of the belt 40 is placed over the plastic stream and between the upturned elongated edges of belt 38. The belt 40 and the die pieces 43 carried thereby cooperate with the lower portion of the belt channel while they move as a unit through travel segment E to form the mold cavity for the rodlike member 35. At the downstream end of travel segment E, a second stream of molten plastic from nozzle 37 is deposited onto the exposed (upper) surface of belt 40, the latter being positioned between the uptumed elongated edges of belt 38. Subsequent to the second stream of plastic being deposited onto belt 40, the two belts move as a unit through travel segment F. While traveling through segment F, the belts pass through a stationary fonning unit 45, which further deforms belt 38 into a cylindrically shaped member or tube T, see FIG. 8. The tube T encompases the two streams of plastics which are separated from one another by the encompasses belt 40. Subsequent to belt 38 assuming its tubular shape, the two belts and the accommodated plastic streams continue to moveas a unit through the remainder of travel segment F whereupon the plastic is cured and then cooled.

At the downstream end of forming unit 45, the encompassing tubular belt 38 is returned to its planar shape by suitable plows, not shown, prior to the belt reaching pulley 41b. Because of the member 35 being released from belt 38 and the latter being moved about the periphery of pulley 411) the member 35 will have an inherent tendency to bow downwardly a slight amount causing the member 35 to become disengaged from the underside of belt 40.

A short distance downstream from the pulley 41b and ahead of pulley 42b, belt 40 is disengaged from the underside of member 35 whereupon the latter is deflected to one side of pulley 42b so as to clear same. The belt 40 is then guided back to a position whereby it will move about the periphery of pulley 42b.

Once the two members 35 and 35' have been freed from the belts 38 and 40, they are directed to a former, not shown, wherein the perforated membrane is sandwiched between the adjacent planar surfaces of the members. Once the membrane has been properly positioned, the composite unit is directed past a cutter, not shown, wherein filters 10 of appropriate size are cut therefrom.

While the complemental sections have heretofore been described as being formed by a continuous molding operation, it is to be understood of course that said sections may be formed by other means such as injection molding or the like.

The length of the complemental sections 12 and 13; the shape and size of the indentation 14 formed in the sections; and the shape and number of perforations formed in the membrane may be varied from that shown without departing from the scope of the disclosed invention.

While the filter 10 has been described relative to a cigarette, it may also be affixed to the end of a cigar, or used as a filter which can be separated from the cigarette rod or cigar and reused, or it can be incorporated in a pipe stem.

Thus, it will be seen that a filter of extremely simple design has been provided wherein the component parts thereof may be automatically and expeditiously formed and assembled by well known automatic apparatus. Furthermore, the filter assembly is of sturdy construction and not readily susceptible to collapse. The configurations of the passageways formed in the filter assembly remain uniform and are not adversely affected by the normal finger or lip pressure applied to the filter during smoking.

lclaim:

1. In a filter cigarette, a filter assembly in unitary relation with one end of a tobacco rod, said assembly comprising a pair of elongated semicylindrical complemental sections arranged in registered relation so as to form a substantially cylindrical member axially aligned and aflixed to the tobacco rod one end, each complemental section being of substantially solid one piece construction and formed of a smoke-impervious material and having a substantially flat inner surface provided with an elongated indentation open at only one end, one section indentation open end facing upstream and terminating adjacent the tobacco rod one end, and the other section indentation open end facing downstream, the closed ends of said section indentations being in overlapping relation; and a thin perforated membrane sandwiched between the flat inner surfaces of said complemental sections and spanning the width of each indentation, the indentations of said sections cooperating with said membrane to form a pair of elongated shallow passageways communicating with one another only through a predetermined number of said membrane perforations, the passagewaycommunicating perforations being sized whereby smoke passes therethrough in a direction transversely of the axis of said cylindrical member and at a very high velocity and the emitted smoke impinges against a wall of one of the shallow passageways disposed opposite said perforations and effects deposition on said wall of solid and liquid particles entrained in the emitted smoke.

2. The filter assembly of claim 1 wherein said complemental sections are fonned of a foam plastic material.

3. The filter assembly of claim 1 wherein the membrane perforations effecting communication between said passageways are circular and have a diameter of from about 0.008 inch to about 0.012 inch, the thickness of said membrane is from about 0.0003 inch to about 0.010 inch, and the distance between said membrane perforations and the impingement wall forming one of said passageways is from about 0.008 inch to about 0.100 inch.

4. The filter assembly of claim 1 wherein the portion of the indentation against which the high velocity smoke impinges is disposed in closer proximity to the membrane than the remainder of said indentation.

5. A smoke filter afiixed to the downstream end of a tobacco rod or the like, said filter comprising means defining a longitudinally extending first passageway closed at its downstream end and through which the smoke is adapted to flow from said rod, a thin planar perforated membrane lying in a plane parallel to the longitudinal axis of said rod and having a plurality of small perforations through which smoke is adapted to pass in the form of a plurality of high velocity jets upon leaving said first passageway in a direction substantially perpendicular to said axis, and means defining a shallow second passageway closed at its upstream end and separated from said first passageway by said membrane and into which the smoke jets are adapted to flow and impinge against a wall of said second passageway closely adjacent to and opposite said membrane perforations.

6. The filter recited in claim 5 wherein said membrane is sandwiched between said first and second passageway def'ming means.

7. The filter recited in claim 5 wherein said first and second passageway defining means comprise complemental smoke barrier sections having opposing parallel planar surfaces between which said membrane is sandwiched, each planar surface having a longitudinally extending indentation defining with said membrane said first and second passageways. 

1. In a filter cigarette, a filter assembly in unitary relation with one end of a tobacco rod, said assembly comprising a pair of elongated semicylindrical complemental sections arranged in registered relation so as to form a substantially cylindrical member axially aligned and affixed to the tobacco rod one end, each complemental section being of substantially solid one piece construction and formed of a smoke-impervious material and having a substantially flat inner surface provided with an elongated indentation open at only one end, one section indentation open end facing upstream and terminating adjacent the tobacco rod one end, and the other section indentation open end facing downstream, the closed ends of said section indentations being in overlapping relation; and a thin perforated membrane sandwiched between the flat inner surfaces of said complemental sections and spanning the width of each indentation, the indentations of said sections cooperating with said membrane to form a pair of elongated shallow passageways communicating with one another only through a predetermined number of said membrane perforations, the passageway-communicating perforations being sized whereby smoke passes therethrough in a direction transversely of the axis of said cylindrical member and at a very high velocity and the emitted smoke impinges against a wall of one of the shallow passageways disposed opposite said perforations and effects deposition on said wall of solid and liquid particles entrained in the emitted smoke.
 2. The filter assembly of claim 1 wherein said complemental sections are formed of a foam plastic material.
 3. The filter assembly of claim 1 wherein the membrane perforations effecting communication between said passageways are circular and have a diameter of from about 0.008 inch to about 0.012 inch, the thickness of said membrane is from about 0.0003 inch to about 0.010 inch, and the distance between said membrane perforations and the impingement wall forming one of said passageways is from about 0.008 inch to about 0.100 inch.
 4. The filter assembly of claim 1 wherein the portion of the indentation against which the high velocity smoke impinges is disposed in closer proximity to the membrane than the remainder of said indentation.
 5. A smoke filter affixed to the downstream end of a tobacco rod or the like, said filter comprising means defining a longitudinally extending first passageway closed at its downstream end and through which the smoke is adapted to flow from said rod, a thin planar perforated membrane lying in a plane parallel to the longitudinal axis of said rod and having a plurality of small perforations through which smoke is adapted to pass in the form of a plurality of high velocity jets upon leaving said first passageway in a direction substantially perpendicular to said axis, and means defining a shallow second passageway closed at its upstream end and separated from said first passageway by said membrane and into which the smoke jets are adapted to flow and impinge against a wall of said second passageway closely adjacent to and opposite said membrane perforations.
 6. The filter recited in claim 5 wherein said membrane is sandWiched between said first and second passageway defining means.
 7. The filter recited in claim 5 wherein said first and second passageway defining means comprise complemental smoke barrier sections having opposing parallel planar surfaces between which said membrane is sandwiched, each planar surface having a longitudinally extending indentation defining with said membrane said first and second passageways. 